Short fat god (3)
I believe the answer is:
lar
'god' is the definition.
(protective household god in ancient Rome)
'short fat' is the wordplay.
'short' means to remove the last letter.
'fat' becomes 'lard' (lard is a kind of fat).
'lard' with its final letter taken off is 'LAR'.
(Other definitions for lar that I've seen before include "Roman household god" , "Libya" , "What's supposed to protect the house" , "statue of a god" .)